The NPCs now may have a (very subtle) blob shadow. I wanted to add this for ages, but i hadn't figured out how to do it efficiently on Android. After all, a simple flat shadow plane that moves with the character won't work in this terrain. It has to adopt to the terrain to a degree but i couldn't use a projective texture either. So i had to look for a way to make a plane roughly follow the terrain without impacting performance...and this is it:

Nothing noticable. The plane is shifted a few units up, which you usually can't see. I tested it on desktop, Adreno and Tegra so far and it works fine on them. I'll try on PowerVR once the damn slow Nexus S has finished all updates that it thinks it has to install (haven't turned it on for some weeks). The Mali device is on holiday together with my wife, so i can't try that ATM...

... using collisions similar to car sample? ie: 4 collisions for 4 corners of plane?

No, not exactly. That was my first idea but it had the problem that it was much too slow on Android to do it that way. But i already have this height map that i'm using for npc movement anyway and i have a method that returns the current height at any point based on this height map and a strange linear interpolation. I'm using this to take three samples around the enemies position and calculate the normal vector of the plane that these three points span. I'm then using a linear interpolation between this vector and the former one and rotate the shadow plane to match the resulting vector.So...it's a linear interpolation of a linear interpolation of some height map values...sounds strange but works pretty well.